The answer depends on your location and how much time tomatoes need before frost

It is not too late to plant tomatoes if you have at least 50 to 80 days before your first fall frost, depending on the variety. Early-maturing types like 'Early Girl' and 'Stupice' can produce fruit in 50 to 60 days. Larger slicing tomatoes like 'Brandywine' need 70 to 85 days. If your first frost typically arrives in late September and it is now mid-July, you have time. If it is mid-August and frost comes in early October, you are cutting it close but may still succeed with fast varieties.

The real constraint is not the calendar date but the number of frost-free days remaining in your growing season. You can find your average first frost date through your local cooperative extension office or by searching "[your city] first frost date." Count backward from that date to today. If you have fewer than 50 days left, starting from seed indoors is risky because seedlings take 6 to 8 weeks to reach transplant size. Buying transplants from a nursery shortens this timeline significantly.

Key Takeaways

  • Early tomato varieties mature in 50 to 60 days; standard types need 70 to 85 days, so check how many frost-free days remain in your growing season.
  • Buying transplants from a nursery is faster than starting from seed, cutting 6 to 8 weeks off the timeline.
  • Tomatoes planted in late summer often produce less total fruit than spring plantings but can still yield a harvest before frost.
  • Soil temperature matters as much as air temperature—tomatoes need soil at least 60°F to germinate and 65°F to grow well.
  • Using black plastic mulch or row covers can warm the soil and extend your growing window by 2 to 3 weeks.

How many days until your first frost determines whether planting makes sense

Your local first frost date is the single most important number. This is the average date when temperatures drop to 32°F in your area. Tomatoes stop growing and die when exposed to frost. The USDA Hardiness Zone map and your cooperative extension website both publish this date for your county or zip code.

Once you know the date, count the days between today and that date. Subtract 7 to 10 days as a safety margin—you want fruit to mature before the very last possible day. If you have 60 days or more, transplants are a reasonable choice. If you have 40 to 50 days, stick to the fastest varieties and use soil warmers. If you have fewer than 40 days, the odds of a meaningful harvest drop sharply, though a few early fruits may still form.

Transplants from a nursery are much faster than seeds

A tomato seed takes 6 to 8 weeks to grow into a transplant large enough to plant outdoors. If you buy transplants that are already 6 to 8 inches tall with visible flower buds, you skip that entire phase. This is the main reason late-season planting is possible at all.

When you buy transplants, look for plants that are stocky and dark green, with no flowers yet open. Flowering transplants have already used energy that could go into root development. Check the label for the variety name and days to maturity. Ask the nursery staff which varieties they have in stock that mature fastest—they usually know which ones perform well in your area.

Soil temperature matters more than air temperature in late summer

Tomato roots grow slowly in cool soil, even if the air is warm. Soil needs to be at least 60°F for seeds to germinate and 65°F for transplants to establish roots quickly. In late summer, soil temperature often lags behind air temperature because the sun is lower in the sky and days are getting shorter.

You can check soil temperature with a soil thermometer, which costs $10 to $20 and takes a reading 4 inches deep where roots actually grow. If soil is below 60°F, wait a week or two and check again. If you are planting in late August or September and soil temperature is borderline, use black plastic mulch to warm it. Lay the plastic over the soil for 7 to 10 days before planting to trap heat, then cut holes and plant through it. This can raise soil temperature 5 to 10 degrees and speed root establishment.

Early and fast-maturing varieties are your best bet for late planting

Not all tomato varieties have the same timeline. 'Early Girl' produces fruit in 50 to 60 days and is widely available at nurseries. 'Stupice' is a cold-tolerant heirloom that matures in 55 to 65 days and produces smaller but flavorful fruit. 'Glacier' is another cold-hardy type that reaches maturity in 55 to 70 days. These are your safest choices if you are planting in late July or early August.

Avoid large slicing tomatoes like 'Brandywine', 'Cherokee Purple', or 'Mortgage Lifter' if you have fewer than 75 days left. These need the full season and rarely produce much fruit if planted late. Cherry tomatoes like 'Sungold' and 'Sweet 100' fall in the middle—they mature in 60 to 70 days and produce prolifically once they start, so they can work for late planting if you have at least 65 days remaining.

Late-season tomatoes produce less fruit but can still be worth planting

A tomato planted in mid-summer will not produce as much total fruit as one planted in spring. The plant has less time to grow large and less time to set fruit before temperatures drop. However, it will still flower and produce some fruit, often in a concentrated burst in early fall.

Late plantings also tend to have fewer disease problems because they avoid the peak humidity of midsummer. Fungal diseases like early blight and septoria leaf spot are less aggressive in cooler, drier fall weather. This can offset the shorter growing season in terms of plant health, even if total yield is lower.

Row covers and mulch extend your growing window

If your first frost date is close but not impossible, use row covers to protect plants from light frosts. Lightweight fabric row covers (sold as frost cloth or frost blanket) let light and water through but trap heat and can protect plants down to about 28°F. Drape the cover over the plants in the evening when frost is forecast and remove it the next morning. This can buy you 2 to 3 weeks of growing time.

Mulch around the base of plants with 2 to 3 inches of straw or wood chips. Mulch keeps soil warm longer as air temperatures drop in fall, which helps roots continue absorbing water and nutrients even when the air is cold. It also moderates soil temperature swings, which reduces stress on the plant.

Frequently Asked Questions

Can I plant tomatoes in August where I live?

Yes, if your first frost date is at least 60 days away and you buy transplants rather than starting from seed. Check your local frost date, count the days remaining, and choose a fast-maturing variety. If you have fewer than 50 days, the odds of a harvest are low.

What if I plant tomatoes too late and frost comes before they ripen?

Pick all the tomatoes on the plant, even if they are still green. Place them in a cardboard box at room temperature (68 to 72°F) away from direct sunlight. They will ripen over 1 to 3 weeks. Ripe tomatoes can also be picked and stored in the refrigerator for up to a week.

Do late-planted tomatoes need different care than spring plantings?

Water and fertilize the same way, but watch for cooler nights starting in September. Reduce nitrogen fertilizer in late summer because excess nitrogen promotes leafy growth at the expense of fruit. Use a balanced or slightly higher-phosphorus fertilizer to encourage flowering and fruiting.

Is it better to wait until next spring if it is too late now?

If you have fewer than 50 frost-free days remaining, yes. A spring planting will produce far more fruit and give you a longer harvest window. Late-season planting works only if you have realistic expectations about yield and are willing to use row covers or other protection.